Will need a follow up from someone who's active, or at least spent more time in-game than I did.

Jita's the busiest economic hub in the game, so they're effectively shutting down a sizable chunk of the game's trade. Though it's in a secure area, inasmuch as the in-game police will kill you for attacking other players, so many ships are involved that they can just suicide attack even the larger vessels before being stopped.

I doubt this will actually "break" the economy though. I imagine it will be disrupted for a time until the campaign ends or trade moves elsewhere.